Method for prolonging service life of catalyst in preparation process of 2-methoxy olefin, metal organic framework material and preparation method of metal organic framework material

Abstract

The invention relates to the field of catalytic reaction, and discloses a method for prolonging the service life of a catalyst in the preparation process of 2-methoxypropene, a metal organic framework material and a preparation method of the metal organic framework material. The method for prolonging the service life of the catalyst in the preparation process of the 2-methoxy olefin comprises the step of carrying out cracking reaction on 2, 2-dimethoxy alkane in the presence of the catalyst. The method has the advantages of high catalytic activity, stable catalyst structure, repeated use, long service life, realization of the reaction in a gas phase at a low temperature, simple post-treatment, realization of product separation in a simple manner, high synthesis efficiency and low production cost.

Description

Technical Field

[0001] The invention relates to the field of catalytic reaction, and in particular to a method for improving the life of a catalyst in a 2-methoxyolefin preparation process, a metal organic framework material and a preparation method thereof. Background Art

[0002] In many synthetic drugs, 2-methoxypropylene is a very important synthetic raw material, especially for the synthesis of clarithromycin, where it is a key intermediate. Clarithromycin is a new type of macrolide antibiotic with broad spectrum, high efficiency and low toxicity developed by Taisho Pharmaceutical Co., Ltd. of Japan, which has very good clinical efficacy in the treatment of infections of accessory organs.

[0003] 2-Methoxypropene was initially prepared by liquid phase cracking of 2,2-dimethoxypropane, mostly using alkanes as solvents and sulfonic acids as catalysts. However, this method was gradually eliminated due to the relatively troublesome post-processing and the corrosion of industrial equipment by large amounts of sulfonic acid. In 1982, Marianne et al. published a study in Tetrahedron Letters, 1982, 23 (6): 631-634. They used neononanoic acid as a catalyst. After 4 hours of reaction, the yield of 2-methoxypropene could reach 71.0%. However, fixed bed reactions could not be performed using organic acids, i.e., separation of the product and the catalyst required distillation or other methods. The work published by Li Xiaoxi et al. in Anhui Chemical Industry, 2009, 35(6): 29-30 in 2009 was improved on this basis. Toluene was used to replace diethylene glycol dimethylbenzene (14.6 mL) as solvent, succinic anhydride (20 g), pyridine (15.6 mL), and benzoic acid (0.58 g) were used as catalysts. The yield could reach 81%, and the product purity could reach 97%. Pyridine and other acidic agents were used for acid regulation. However, it was still a homogeneous reaction, and the catalyst was complex and the separation of the catalyst and the product was difficult. This process reduced the amount of diethylene glycol dimethyl ether used and protected the environment. However, due to the defects of diethylene glycol dimethyl ether such as high price, high toxicity, high boiling point, and easy miscibility with water, further improvement is needed. Dietrich et al. published patent 5767325.1998-6-16 in 1998. The work used ZSM-5 catalyst for gas-phase catalytic cracking of 2,2-dimethoxypropane. The reaction temperature was between 280℃ and 340℃. The product yield reached 83.3%, and the catalyst activity before and after the reaction hardly decreased. The advantage of this synthesis process is that the catalyst is easy to recover, and the disadvantage is that the preparation of the catalyst is relatively complicated. In the synthesis of 2-methoxypropylene, the use of a solid-phase catalyst method can better meet the needs of industrialization, but its disadvantage is that the catalyst is easily deactivated, which leads to increased costs.

[0004] At present, there are still many problems in the synthesis of 2-methoxypropylene. Finding an effective industrial route for preparing 2-methoxypropylene with a heterogeneous catalytic system is a very important research topic. At the same time, it is also necessary to solve the control of the acidity of the catalyst in the heterogeneous system, realize the reaction at a lower temperature, and at the same time ensure the yield and purity of the product, as well as realize the simple separation of the materials after the reaction, and realize the recycling and reuse of the catalyst to increase the service life of the catalyst, and control the coking problem during the reaction. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned problems existing in the prior art and provide a method for improving the life of a catalyst in the preparation process of 2-methoxyolefin and a metal organic framework material and a preparation method thereof. The method has high catalytic activity, a stable catalyst structure, can be repeatedly used, has a long life, can react at a low temperature in the gas phase, has simple post-processing, can separate products in a simple manner, has high synthesis efficiency, and has low production cost.

[0006] In order to achieve the above object, the present invention provides a method for improving the life of a catalyst in a 2-methoxyolefin preparation process, the method comprising: in the presence of a catalyst, subjecting 2,2-dimethoxyalkane to a cracking reaction; wherein the catalyst is a metal organic framework material, the ligand of the metal organic framework material is provided by a substance having a structure as shown in formula (1) and the coordination metal M is selected from one of Zn, Co and Zr; in formula (1), M" comprises H and a metal element, and the metal element is selected from at least one of Li, Na, K, Cs, Ca and Mg;

[0007]

[0008] The second aspect of the present invention provides a metal organic framework material, which is the metal organic framework material as defined in the first aspect or the partially acidified product as described in the first aspect.

[0009] The third aspect of the present invention provides a method for preparing a metal organic framework material, which is a method for preparing the partially acidified product as described in the first aspect.

[0010] The method provided by the present invention has high catalytic activity, stable catalyst structure, can be repeatedly used, has a long service life, can react at a low temperature in the gas phase, has simple post-processing, can separate products in a simple manner, has high synthesis efficiency, and has low production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is the thermogravimetric diagram of the metal organic framework material prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0012] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0013] In a first aspect, the present invention provides a method for improving the life of a catalyst in a 2-methoxyolefin preparation process, the method comprising: performing a cracking reaction on 2,2-dimethoxyalkane in the presence of a catalyst; wherein the catalyst is a metal organic framework material, the ligand of the metal organic framework material is provided by a substance having a structure as shown in formula (1) and the coordination metal M is selected from one of Zn, Co and Zr; in formula (1), M" comprises H and a metal element, and the metal element is selected from at least one of Li, Na, K, Cs, Ca and Mg;

[0014]

[0015] The inventors of the present invention have found in research that when the above method is used to prepare 2-methoxy olefins, the catalytic activity is high, and the catalytic activity is much higher than the activity of catalysts such as sulfonic acid, benzoic acid, ZSM-5 and acidic alumina conventionally used at present, which greatly improves the synthesis efficiency of 2-methoxy olefins; and the catalyst has a stable structure, can be used repeatedly, has a long service life, can reduce the environmental pollution caused by the preparation of the catalyst, and significantly reduces the synthesis cost of 2-methoxy olefins; the reaction can be carried out at a relatively low temperature, and can be reacted in a fixed bed, the product and yield and purity are relatively high, and the product and catalyst are simply separated after the reaction. As a very important drug intermediate, the improvement of the synthesis efficiency of 2-methoxy olefins can greatly reduce its synthesis cost, which is extremely important for the development of the pharmaceutical industry.

[0016] It can be understood that in order to obtain 2-methoxyolefin by cracking, the carbon number of 2,2-dimethoxyalkane is greater than or equal to 3, for example, it can be 2,2-dimethoxypropane, 2,2-dimethoxybutane, etc. According to a particularly preferred embodiment of the present invention, the 2,2-dimethoxyalkane is 2,2-dimethoxypropane, and the 2-methoxyolefin is 2-methoxypropylene.

[0017] According to the present invention, preferably, the metal organic framework material has an average particle size of 0.4-10 μm and a specific surface area of ​​200-1000 m 2 / g, the pore volume is 1-5ml / g, and the most probable pore diameter is 0.1-4nm.

[0018] Preferably, the metal organic framework material has an average particle size of 0.5-5 μm and a specific surface area of ​​250-800 m 2 / g, the pore volume is 1.1-3ml / g, and the most probable pore diameter is 0.2-3.5nm.

[0019] Preferably, the metal organic framework material has an average particle size of 1-3 μm and a specific surface area of ​​300-760 (for example, 300, 320, 350, 380, 400, 420, 450, 480, 500, 550, 600, 650, 700, 750, 760, and a range formed by any two of the above values ​​and a value within the range) m 2 / g, a pore volume of 1.2-2.7 (for example, it can be 1.2, 1.4, 1.5, 1.8, 2, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7 and the range formed by any two of the above values ​​and the value within the range) ml / g, and a most probable pore diameter of 0.3-3 (for example, it can be 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3 and the range formed by any two of the above values ​​and the value within the range) nm.

[0020] According to the present invention, preferably, the metal organic framework material has a structure as shown in formula (2):

[0021]

[0022] As described above, it can be understood that the metal organic framework material also has a structure in which H in -SO3H in formula (2) is replaced by the above-mentioned optional metal.

[0023] According to the present invention, preferably, in M", the molar ratio of the metal element to H is (0.001-1000):1, preferably (0.005-50):1, and more preferably (0.1-1.5):1. That is, the catalyst may include a structure in which M" is H, and M" is the above-mentioned metal element. The catalyst is acidic, has a stable sulfonic acid group, and its skeleton structure is stable in water and an organic solvent. The catalyst provided by the present invention can generally exist relatively stably. In addition, the acidity of the catalyst can be adjusted by adjusting the molar ratio of the above-mentioned metal element to H. The reaction is sensitive to the acidity of the catalyst. Under suitable acidic conditions, the reaction can be carried out at a lower temperature, and the yield and purity of the product can be guaranteed at the same time. The molar ratio of the above-mentioned metal element to H (that is, the ratio of the sulfonic acid metal salt to the sulfonic acid group) can generally be determined by thermogravimetry. On the thermogravimetric curve, the weight of the metal organic framework material mainly loses weight three times as the temperature rises. The first weight loss is caused by the sulfonic acid group, the second weight loss is caused by the sulfonic acid metal salt group, and the last weight loss is caused by the complete combustion of the organic framework.

[0024] According to the present invention, preferably, the method for preparing the catalyst comprises:

[0025] (1) in the presence of a first solvent and an organic acid, causing the compound represented by formula (3) to undergo a coordination reaction with a metal source to be coordinated;

[0026] (2) partially acidifying the product of the coordination reaction in the presence of an inorganic acid;

[0027] Wherein, in formula (3), M' is selected from one of Li, Na, K, Cs, Ca and Mg; the metal M in the metal source to be coordinated is selected from one of Zn, Co and Zr;

[0028]

[0029] The acidification may cause the metal M' to be at least partially replaced by H.

[0030] According to the present invention, preferably, in step (1), the conditions of the coordination reaction include: a temperature of 80-150°C, preferably 90-100°C (for example, it can be 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, and the range formed by any two of the above values, and the values ​​within the range)°C; a time of 20-30h, preferably 22-26 (for example, it can be 22, 23, 24, 25, 26, and the range formed by any two of the above values, and the values ​​within the range)h.

[0031] According to the present invention, preferably, in step (1), the molar ratio of the metal source to be coordinated, the compound represented by formula (3), the first solvent and the organic acid is (0.8-6):1:(3-120):(0.5-25), preferably (2-3):1:(5-80):(0.5-15).

[0032] According to the present invention, preferably, in step (1), the metal source to be coordinated is selected from at least one of ZrCl4, Co(NO3)2 and Zn(acac)2. Zn(acac)2 refers to zinc acetylacetonate. Hydrates corresponding to the above substances may also be used, such as Cr(NO3)3·6H2O.

[0033] According to the present invention, preferably, the first solvent is selected from at least one of N,N-dimethylformamide (DMF), dimethyl sulfoxide and N-methylpyrrolidone, preferably N,N-dimethylformamide.

[0034] According to the present invention, preferably, in step (1), the organic acid is selected from at least one of formic acid, acetic acid, benzoic acid and phenylacetic acid.

[0035] After the coordination reaction, the material can be centrifuged and filtered, and the solid obtained after the filtration can be washed and dried in sequence. The centrifugal condition can be 3500-6500rpm, and the time can be 10-60min; in the washing, DMF can be used for washing 2-4 times, and then methanol can be used for washing 2-4 times, and the amount of detergent used in the washing is not particularly limited. The drying temperature can be 100-130°C, and the time can be 2-10h.

[0036] According to the present invention, preferably, in step (2), the inorganic acid is selected from at least one of hydrochloric acid, sulfuric acid and nitric acid, preferably hydrochloric acid. The solid product obtained in step (1) can be mixed with an aqueous solution of the acid, and the concentration of the acid in the aqueous solution of the acid can be 0.8-8 mol / L.

[0037] According to the present invention, preferably, the conditions for partial acidification include: a temperature of 15-65°C (for example, it can be 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C and any range formed by any two of the above values ​​and values ​​within the range), and a time of 1-10h (for example, it can be 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h and any range formed by any two of the above values ​​and values ​​within the range).

[0038] According to the present invention, preferably, the amount of the inorganic acid used is 0.01-0.99 mol per mole of the compound represented by formula (3), so as to ensure partial acidification and achieve the purpose of controllable acidity.

[0039] After the partial acidification is completed, the material obtained by partial acidification can be filtered, and the obtained solid can be washed with water for 2-4 times. There is no particular limitation on the amount of water used for washing.

[0040] The present invention has no particular limitation on the method for obtaining the compound represented by formula (3). Preferably, the preparation step of the compound represented by formula (3) comprises: in the presence of a second solvent and a metal halide, subjecting terephthalic acid to a substitution reaction with chlorosulfonate.

[0041] According to the present invention, preferably, the conditions of the substitution reaction include: a temperature of 30-105°C, preferably 40-70°C (for example, it can be 40, 45, 48, 49, 50, 51, 52, 53, 55, 58, 60, 65, 70, and a range formed by any two of the above values, and a value within the range)°C; a time of 3-30h, preferably 5-28 (for example, it can be 5, 6, 7, 8, 10, 12, 18, 20, 22, 23, 24, 26, 28, and a range formed by any two of the above values, and a value within the range)h.

[0042] According to the present invention, preferably, the molar ratio of terephthalic acid, chlorosulfonate and metal halide is 1:(0.7-1.5):(0.01-0.1).

[0043] According to the present invention, preferably, the metal halide is selected from RuCl3 and / or FeCl3.

[0044] According to the present invention, preferably, the second solvent is selected from chlorobenzene and / or dichloromethane. The amount of the second solvent is not particularly limited. For example, relative to 1g of terephthalic acid, the amount of the second solvent can be 30-100 (for example, 30, 40, 50, 60, 70, 80, 90, 100 and the range formed by any two of the above values ​​and the value within the range) ml.

[0045] The metal element in the chlorosulfonate is based on M'.

[0046] After the substitution reaction is completed, the material after the substitution reaction can be filtered, washed and dried in sequence. The washing can be firstly carried out with the same detergent as the second solvent for 2-4 times, and then washed with methanol for 2-4 times; the drying temperature can be 80-120°C and the drying time can be 2-8h.

[0047] According to the present invention, preferably, the cracking reaction comprises: passing a gas containing 2,2-dimethoxyalkane into a reactor loaded with a catalyst.

[0048] According to a preferred embodiment of the present invention, the reactor is a fixed bed reactor. The catalyst is filled in the fixed bed reactor, and gas is introduced to carry out the reaction.

[0049] Preferably, the amount of gas containing 2,2-dimethoxyalkane introduced is such that the space velocity of 2,2-dimethoxyalkane is 1000-6000 (for example, 1000, 2000, 3000, 4000, 5000, 6000, and ranges formed by any two of the above values, and values ​​within the range) ml / h.

[0050] The gas containing 2,2-dimethoxyalkane uses an inert gas as a carrier gas, and the inert gas can be selected from at least one of nitrogen, helium and argon.

[0051] According to the present invention, preferably, the conditions of the cleavage reaction include: a temperature of 25-220° C., preferably 45-155° C. (for example, it can be 45, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 155, and a range formed by any two of the above values ​​and a value within the range)° C. The method provided by the present invention can carry out the cleavage reaction at a lower temperature than the prior art, and the synthesis cost is lower.

[0052] According to the present invention, preferably, after the cracking reaction, the method further comprises: distilling the liquid phase obtained by the cracking reaction. The liquid phase obtained after the reaction generally contains 2-methoxyolefin, methanol and 2,2-dimethoxyalkane, and the 2-methoxyolefin can be fully purified by distillation. The method of the present invention can separate and purify 2-methoxyolefin in a simple manner.

[0053] According to the present invention, preferably, the distillation is carried out in a distillation tower, and the distillation temperature is 20-80° C., preferably 45-70° C. (for example, it can be 45, 50, 55, 60, 65, 70, and the range formed by any two of the above values ​​and the value within the range)° C. The vacuum distillation can be carried out at 0.1-0.5 atm.

[0054] In a second aspect, the present invention provides a metal organic framework material, which is the metal organic framework material defined in the first aspect or the partially acidified product described in the first aspect.

[0055] In a third aspect, the present invention provides a method for preparing a metal organic framework material, which is the method for preparing the partially acidified product described in the first aspect.

[0056] The present invention will be described in detail below through examples.

[0057] In the following examples, the average particle size was determined by Thermo Scientific TM The specific surface area, pore volume and most probable pore diameter were measured by Apreo scanning electron microscope, and the specific surface area, pore volume and most probable pore diameter were measured by physical adsorption instrument AntonPaar QuantaTec. In the catalyst, the molar ratio of metal element and H in M" was determined by the ratio of sulfonate metal salt to sulfonate, that is, by thermogravimetry: the weight of the material mainly loses weight three times as the temperature increases, the first weight loss is caused by the sulfonate weight loss, and the second weight loss is caused by the sulfonate metal salt. Taking the metal organic framework material prepared in Example 1 as an example, Figure 1 As shown, the weight loss around 300-500°C is caused by sulfonate radicals, and the weight loss around 500-600°C is caused by sulfonate metal salt radicals.

[0058] In the following examples, the reaction tube used for the cracking reaction (using a fixed bed reaction) is 1 meter long and 1 centimeter in inner diameter.

[0059] In the following examples, the liquid phase obtained after the reaction was distilled (50° C., reduced pressure distillation at 0.2 atm) to separate 2-methoxypropylene, methanol and 2,2-dimethoxypropane, and each substance and its corresponding content were confirmed by GC.

[0060] In the following examples, the conversion rate of 2,2-dimethoxypropane is calculated as follows: 100% - mass percentage of 2,2-dimethoxypropane in the liquid phase obtained by the reaction;

[0061] The reaction selectivity is calculated by the ratio of the sum of the amount of 2-methoxypropylene and the amount of methanol in the liquid phase obtained by the reaction to the conversion rate of 2,2-dimethoxypropane.

[0062] Example 1

[0063] (1) Preparation of acidic metal organic framework material 1, wherein the corresponding coordination metal M is Zn, and M" is H and Na.

[0064] 0.8 g of FeCl3, 16.6 g of terephthalic acid, 16.5 g of sodium chlorosulfonate and 1000 mL of dichloromethane were added to the reaction bottle, and the substitution reaction was carried out at 50°C for 5 h. The solid was filtered and washed three times with 100 mL of dichloromethane and three times with 100 mL of methanol, and dried at 80°C for 8 h to obtain a white powder (NMR detection confirmed that it was the compound represented by formula (3), wherein M' is Na).

[0065] Afterwards, Zn(acac)2, the compound represented by the above formula (3), DMF and acetic acid were subjected to coordination reaction (calcination crystallization) in a molar ratio of 2.5:1:40:6 at 95°C for 24 hours, centrifuged at 4000 rpm for 50 minutes, and then filtered. The solid was washed three times with 50 mL of DMF and three times with 50 mL of methanol. The solid was dried at 105°C for 8 hours to obtain a white solid.

[0066] Add 5 mol / L hydrochloric acid to the obtained white solid, in an amount such that the amount of hydrochloric acid used is 0.06 mol per mole of the compound represented by formula (3), and acidify for 3 hours under stirring at 25°C; filter and rinse the solid three times with 50 mL of water to obtain a partially acidified metal organic framework material (XRD and electron microscope scanning images confirm that the same framework structure as in formula (2) is obtained, wherein Zn is the coordination metal). The average particle size of the obtained metal organic framework material is 2.5 μm, and the specific surface area is 503 m 2 / g, pore volume is 2.1ml / g, and the most probable pore diameter is 1.2nm. The molar ratio of sulfonic acid metal salt to sulfonic acid group in this catalyst is 0.5:1.

[0067] (2) Preparation of 2-methoxypropene: The acidic metal organic framework material prepared in step (1) was loaded into a reaction tube with a loading length of 1 cm. The amount of gas containing 2,2-dimethoxypropane (carrier gas is nitrogen) introduced was such that the space velocity of 2,2-dimethoxypropane was 3000 ml / h, the reaction temperature was 100° C., and the reaction product was monitored by GC (gas chromatography). After the reaction was stable for 1 hour, the mass contents of 2-methoxypropene, methanol and 2,2-dimethoxypropane in the liquid phase obtained by the reaction were 68.4 wt%, 30.3 wt% and 0.5 wt%, respectively, that is, the conversion rate was 99.5% and the selectivity was 99.2%. After 700 hours of reaction, the content of 2-methoxypropene began to decrease, indicating that the reaction life of the above catalyst can reach 700 hours.

[0068] Example 2

[0069] (1) Preparation of acidic metal organic framework material 2, wherein the corresponding coordination metal M is Co, and M" is H and Na.

[0070] 1.04 g of RuCl3, 16.6 g of terephthalic acid, 16.5 g of sodium chlorosulfonate and 1000 mL of dichloromethane were added to the reaction bottle, and the substitution reaction was carried out at 50°C for 5 h. The solid was filtered and washed three times with 100 mL of dichloromethane and three times with 100 mL of methanol, and dried at 80°C for 8 h to obtain a white powder (NMR detection confirmed that it was the compound represented by formula (3), wherein M' is Na).

[0071] Afterwards, Co(NO3)26H2O, the compound represented by the above formula (3), DMF and benzoic acid were subjected to coordination reaction (calcination crystallization) in a molar ratio of 2:1:5:0.5 at 95°C for 24 hours, centrifuged at 5000 rpm for 30 minutes, and then filtered. The solid was washed three times with 50 mL of DMF and three times with 50 mL of methanol. The solid was dried at 105°C for 3 hours to obtain a white solid.

[0072] Add 5 mol / L hydrochloric acid to the obtained white solid, in an amount such that the amount of hydrochloric acid used is 0.09 mol per mole of the compound represented by formula (3), and acidify for 3 hours under stirring at 25°C; filter and rinse the solid with 50 mL of water three times to obtain a partially acidified metal organic framework material (the XRD spectrum and electron microscope scanning image confirm that the same framework structure as in formula (2) is obtained, wherein Co is the coordination metal). The average particle size of the obtained metal organic framework material is 1 μm, and the specific surface area is 752 m 2 / g, the pore volume is 2.7ml / g, the most probable pore diameter is 2.0nm, and the molar ratio of metal salt root to sulfonate root in this catalyst is 1:4.

[0073] (2) Preparation of 2-methoxypropene: The acidic metal organic framework material prepared in step (1) was loaded into a reaction tube with a loading length of 1 cm. The amount of gas containing 2,2-dimethoxypropane (carrier gas is nitrogen) introduced was such that the space velocity of 2,2-dimethoxypropane was 2000 ml / h, the reaction temperature was 120°C, and the reaction product was monitored by GC. After the reaction was stable for 1 hour, the mass contents of 2-methoxypropene, methanol and 2,2-dimethoxypropane in the liquid phase obtained by the reaction were 67.9 wt%, 30.2 wt% and 1.4 wt%, respectively, that is, the conversion rate was 98.6% and the selectivity was 99.4%. After 650 hours of reaction, the content of 2-methoxypropene began to decrease, indicating that the reaction life of the above catalyst can reach 650 hours.

[0074] Example 3

[0075] (1) Preparation of acidic metal organic framework material 3, wherein the corresponding coordination metal M is Zr, and M" is H and Na.

[0076] 1.04 g of RuCl3, 16.6 g of terephthalic acid, 16.5 g of sodium chlorosulfonate and 1000 mL of dichloromethane were added to the reaction bottle, and the substitution reaction was carried out at 50°C for 24 h. The solid was filtered and washed three times with 100 mL of dichloromethane and three times with 100 mL of methanol, and dried at 80°C for 8 h to obtain a white powder (NMR detection confirmed that it was the compound represented by formula (3), wherein M' is Na).

[0077] Afterwards, ZrCl4, the compound represented by the above formula (3), DMF and phenylacetic acid were subjected to coordination reaction (calcination crystallization) in a molar ratio of 3:1:80:12 at 95°C for 24 hours, centrifuged at 6000 rpm for 30 minutes, and then filtered. The solid was washed three times with 50 mL of DMF and three times with 50 mL of methanol. The solid was dried at 105°C for 5 hours to obtain a white solid.

[0078] Add 5 mol / L hydrochloric acid to the obtained white solid, in an amount such that the amount of hydrochloric acid used is 0.07 mol per mole of the compound represented by formula (3), and acidify for 1 hour under stirring at 50°C; filter and rinse the solid with 50 mL of water three times to obtain a partially acidified metal organic framework material (through XRD spectrum and electron microscope scanning, it is confirmed that the same framework structure as in formula (2) is obtained, wherein Zr is the coordination metal). The average particle size of the obtained metal organic framework material is 2 μm, and the specific surface area is 455 m 2 / g, the pore volume is 2.1ml / g, the most probable pore diameter is 3.0nm, and the molar ratio of sulfonate metal salt to sulfonate in this catalyst is 3:7.

[0079] (2) Preparation of 2-methoxypropene: The acidic metal organic framework material prepared in step (1) was loaded into a reaction tube with a loading length of 1 cm. The amount of gas containing 2,2-dimethoxypropane (carrier gas is nitrogen) introduced was such that the space velocity of 2,2-dimethoxypropane was 2000 ml / h, the reaction temperature was 100°C, and the reaction product was monitored by GC. After the reaction was stable for 1 hour, the mass contents of 2-methoxypropene, methanol and 2,2-dimethoxypropane in the liquid phase obtained by the reaction were 67.3wt%, 29.9wt% and 2.1wt%, respectively, that is, the conversion rate was 97.9% and the selectivity was 99.3%. After 800 hours of reaction, the content of 2-methoxypropene began to decrease, indicating that the reaction life of the above catalyst can reach 800 hours.

[0080] Example 4

[0081] The metal organic framework material was prepared according to the method of Example 3, except that sodium chlorosulfonate was replaced by lithium chlorosulfonate, that is, in the obtained acidic metal organic framework material, M" was H and Li, the molar ratio of the metal salt radical to the sulfonate radical in the catalyst was 1:3, and the cracking reaction of step (2) was carried out. After the reaction was stable for 1 hour, the mass contents of 2-methoxypropylene, methanol and 2,2-dimethoxypropane in the liquid phase obtained by the reaction were 68.1wt%, 30.3wt% and 1.3wt%, that is, the conversion rate was 98.7%, and the selectivity was 99.7%.

[0082] Comparative Example 1

[0083] The method of Example 1 was followed, except that UiO-66 material (i.e., no sulfonic acid group on the metal organic framework material) was used as a catalyst, and the results are shown in Table 1. After the reaction was stable for 1 hour, the mass contents of 2-methoxypropylene, methanol, and 2,2-dimethoxypropane in the liquid phase obtained by the reaction were 0, 0, and 99.8 wt%, i.e., the conversion rate was 0.

[0084] Comparative Example 2

[0085] The method of Example 1 was followed, except that, during the acidification, an excess of hydrochloric acid was added to make M" H, i.e., the material was completely acidified. The cracking reaction was then carried out according to step (2) in Example 1. After the reaction was stable for 1 hour, the mass contents of 2-methoxypropylene, methanol and 2,2-dimethoxypropane in the liquid phase obtained by the reaction were 58.8wt%, 27.3wt% and 0.6wt%, respectively, i.e., the conversion rate was 99.4%, but the selectivity was only 87%. This indicates that most of the coking products were carbonized on the catalyst.

[0086] Comparative Example 3

[0087] The method of Example 1 was followed, except that no acidification was performed, i.e., M" was completely Na. A cracking reaction was then performed according to step (2) in Example 1. After the reaction was stable for 1 hour, GC was used to monitor the reaction. The mass contents of 2-methoxypropylene, methanol, and 2,2-dimethoxypropane in the liquid phase obtained by the reaction were 0 wt%, 0 wt%, and 99 wt%, i.e., the conversion rate was 0%, and some of the raw materials were carbonized.

[0088] It can be seen from the above embodiments and comparative examples that the method provided by the present invention has high catalytic activity, can reduce or avoid coking during the reaction, has a stable catalyst structure, can be used repeatedly, has a long life, can react at a lower temperature in the gas phase, and has simple post-processing, can separate the products in a simple manner, has high synthesis efficiency, and has low production cost.

[0089] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for increasing the life of a catalyst in a 2-methoxyolefin preparation process, characterized in that: The method comprises: in the presence of a catalyst, performing a cracking reaction on 2,2-dimethoxyalkane; wherein the catalyst is a metal organic framework material, the ligand of the metal organic framework material is provided by a substance having a structure as shown in formula (1), and the coordination metal M is selected from one of Zn, Co and Zr; in formula (1), M" comprises H and a metal element, and the metal element is selected from at least one of Li, Na, K, Cs, Ca and Mg; 2. The method according to claim 1, wherein: The metal organic framework material has an average particle size of 0.4-10 μm and a specific surface area of ​​200-1000 m 2 / g, pore volume is 1-5ml / g, and the most probable pore diameter is 0.1-4nm; Preferably, the metal organic framework material has an average particle size of 0.5-5 μm and a specific surface area of ​​250-800 m 2 / g, pore volume is 1.1-3ml / g, and the most probable pore diameter is 0.2-3.5nm; Preferably, the metal organic framework material has an average particle size of 1-3 μm and a specific surface area of ​​300-760 m 2 / g, the pore volume is 1.2-2.7ml / g, and the most probable pore diameter is 0.3-3nm.

3. The method according to claim 1, wherein: The metal organic framework material has a structure as shown in formula (2): And / or, in M", the molar ratio of the metal element to H is (0.001-1000):1, preferably (0.005-50):1, and more preferably (0.1-1.5):

1.

4. The method according to claim 1 or 2, wherein: The preparation method of the catalyst comprises: (1) in the presence of a first solvent and an organic acid, causing the compound represented by formula (3) to undergo a coordination reaction with a metal source to be coordinated; (2) partially acidifying the product of the coordination reaction in the presence of an inorganic acid; Wherein, in formula (3), M' is selected from one of Li, Na, K, Cs, Ca and Mg; the metal M in the metal source to be coordinated is selected from one of Zn, Co and Zr; 5. The method according to claim 4, wherein: In step (1), the conditions for the coordination reaction include: temperature of 80-150° C., preferably 90-100° C.; time of 20-30 h, preferably 22-26 h; And / or, in step (1), the molar ratio of the metal source to be coordinated, the compound represented by formula (3), the first solvent and the organic acid is (0.8-6):1:(3-120):(0.5-25), preferably (2-3):1:(5-80):(0.5-15).

6. The method according to claim 4 or 5, wherein: In step (1), the metal source to be coordinated is selected from at least one of ZrCl4, Co(NO3)2 and Zn(acac)2; and / or, the first solvent is selected from at least one of N,N-dimethylformamide, dimethyl sulfoxide and N-methylpyrrolidone, preferably N,N-dimethylformamide; And / or, in step (1), the organic acid is selected from at least one of formic acid, acetic acid, benzoic acid and phenylacetic acid.

7. The method according to claim 4, wherein: In step (2), the inorganic acid is selected from at least one of hydrochloric acid, sulfuric acid and nitric acid, preferably hydrochloric acid; And / or, the partial acidification conditions include: temperature of 15-65°C and time of 1-10h; And / or, the amount of the inorganic acid used is 0.01-0.99 mol per mole of the compound represented by formula (3).

8. The method according to claim 1 or 3, wherein: The cracking reaction method includes: passing a gas containing 2,2-dimethoxyalkane into a reactor loaded with a catalyst; Preferably, the amount of the gas containing 2,2-dimethoxyalkane introduced is such that the space velocity of the 2,2-dimethoxyalkane is 1000-6000 ml / h.

9. The method according to claim 1 or 3, wherein: The conditions of the cleavage reaction include: a temperature of 25-220°C, preferably 45-155°C; And / or, after the cracking reaction, the method further comprises: distilling the liquid phase obtained from the cracking reaction; Preferably, the distillation is carried out in a distillation tower at a distillation temperature of 20-80°C, preferably 45-70°C.

10. A metal organic framework material, characterized in that: The metal organic framework material is the metal organic framework material defined in any one of claims 1 to 3 or the partially acidified product described in any one of claims 4 to 7.

11. A method for preparing a metal organic framework material, characterized in that: The preparation method is a method for preparing the partially acidified product according to any one of claims 4 to 7.

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